KITAKYUSHU, Japan — For a sense of what the United States might look like in a reality where the hard right’s dreams of drastically reduced immigration come true, you could come to Japan and ask my father-in-law about the house across the street. The owner of the house died some time ago in this low-key, working-class suburb of Kitakyushu, in Japan’s southern island. The house has fallen badly into disrepair. None of the heirs seems interested in it: The taxes are too high, and there isn’t really a market for this kind of house anyway.

It’s far from a unique story. Japan’s population is shrinking, with far-reaching consequences that seep into every corner of life here. “Akiya” — abandoned houses like the one blighting my in-laws’ street — are just one sign of it. As the country ages and older people die with no one to replace them, neighborhoods across Japan are also slowly dying.

As many as 8 million houses in Japan are vacant, and the trend is only deepening. Rural villages are disappearing, and more and more Japanese towns and suburbs have become “dying communities” where children are a rare sight; authorities barely manage to find the care workers needed to look after legions of retirees.

Of course, Japan is hardly alone in having an aging population where native-born people’s death rates increasingly outnumber their births. But in just about every other developed country, the houses freed up by the elderly are snapped up by new arrivals — young workers from developing countries in the prime of their lives, eager for a better future for their families.

Not in Japan.

A solid political consensus has rejected mass immigration here for as long as anyone can remember, leaving this one of the most homogeneous countries on earth. You can think of Japan as a kind of Trumpian paradise: an ethnically defined national community with few foreigners. And no future.

The problem has recently become bad enough to force even the conservative administration of Prime Minister Shinzo Abe to rethink its stance on migration. Under strong pressure from the business lobby, which has been desperate for extra workers for years, the government is opening up new routes into the country for foreign workers — but the political schizophrenia around migration is only too evident even in this partial new opening.

The government has begun making more work permits available to foreign workers, but makes little effort to help them integrate. Visa rules force most foreign workers to apply for extensions frequently and prevent them from bringing their families. By all accounts, discrimination in housing is rife, as well as perfectly legal. The foreign workers who do come can’t fail to hear the message: Come, work, but don’t think you’re welcome to stay.

Economic imperatives and cultural consensus are at war in Japan’s immigration debate: It’s no longer possible for the country to continue to pretend it can get by without migrants. But it’s politically impossible to truly welcome them, either. The result is that more and more jobs simply stay vacant, not just in industry and agriculture but also in the kinds of elder-care jobs this aging country most desperately needs to fill.

All the while, invasive bamboo shoots dig deeper into the grounds of the abandoned house across the street from my in-laws’. A huge glut of these kinds of homes and next-to-no demand have driven the market prices for homes like this one all the way down to zero in many cases, setting off a raft of click-baity “Japan Is Giving Away Abandoned Houses for Free” stories in global media.

It’s a half-truth, at best: Many of the houses require thousands of dollars in repairs and maintenance to be habitable, and property taxes have to be paid all the same. But even the half that’s true is misleading: This isn’t a fun, quirky story about “weird” Japan. It’s a bright red warning sign of demographic meltdown, and an indictment of a society that has chosen homogeneity over progress.

In the end, President Trump isn’t wrong: America does have a choice. Japan proves that the choice between homogeneity and diversity is real. It’s just that homogeneity leads to decline, while diversity offers at least a chance of ongoing vitality and prosperity.